1. Field of the Invention
One embodiment of the present invention relates to a method for manufacturing a circuit board. Another embodiment of the present invention relates to a method for manufacturing a light-emitting device. Another embodiment of the present invention relates to a light-emitting device.
Note that one embodiment of the present invention is not limited to the above technical field. One embodiment of the invention disclosed in this specification and the like relates to an object, a method, or a manufacturing method. One embodiment of the present invention relates to a process, a machine, manufacture, or a composition of matter. Specifically, examples of the technical field of one embodiment of the present invention disclosed in this specification include a semiconductor device, a display device, a light-emitting device, a power storage device, a memory device, an electronic device, a lighting device, an input device, an input/output device, a method for driving any of them, and a method for manufacturing any of them.
A circuit board in this specification means a board that includes a circuit including wirings (e.g., a semiconductor device and a light-emitting device). A semiconductor device generally means a device that can function by utilizing semiconductor characteristics. Accordingly, a transistor, a semiconductor element, a semiconductor circuit, an input/output device, a memory device, an imaging device, an electro-optical device, a power generation device (e.g., a thin film solar cell and an organic thin film solar cell), an electronic device, and the like are included in the category of the semiconductor device. A light-emitting device includes, in its category, a display device using a light-emitting element. Furthermore, the light-emitting device may be included in a module in which a light-emitting element is provided with a connector such as an anisotropic conductive film or a tape carrier package (TCP), a module in which a printed wiring board is provided at the end of a TCP, and a module in which an integrated circuit (IC) is directly mounted on a light-emitting element by a chip on glass (COG) method. The light-emitting device may also be included in lighting equipment or the like.
2. Description of the Related Art
In recent years, research and development have been extensively conducted on liquid crystal elements as a display element used in a display region of a display device. In addition, research and development have been extensively conducted on light-emitting elements utilizing electroluminescence (EL). As a basic structure of these light-emitting elements, a layer containing a light-emitting substance is provided between a pair of electrodes. Voltage is applied to this light-emitting element to obtain light emission from the light-emitting substance.
Light-emitting elements are a self-luminous element; thus, a display device using the light-emitting elements has, in particular, advantages such as high visibility, no necessity of a backlight, and low power consumption. The display device using the light-emitting elements also has advantages in that it can be manufactured to be thin and lightweight and has high response speed.
The display device including the display elements can have flexibility; therefore, the use of a flexible substrate for the display device has been proposed.
As a method for manufacturing a display device using a flexible substrate, a technique has been developed in which an oxide layer and a metal layer are formed between a substrate and a semiconductor element, the substrate is separated by utilizing weak adhesion of an interface between the oxide layer and the metal layer, and then the semiconductor element is transferred to another substrate (e.g., a flexible substrate) (Patent Document 1).
Display devices are expected to be applied to a variety of uses and become diversified. For example, a smartphone and a tablet terminal with a touch sensor are being developed as mobile devices.